A study examined the change in blood LDL cholesterol level in millimoles per liter (mmol/L) as a function of baseline LDL when subjects took either a placebo or the drug Pravastatin for two years. One model of the results shows two parallel lines and gives a multiple linear regression model μy=−1.875+0.4375x1+1.4x2 , where x1 represents baseline cholesterol level and x2 is an indicator variable for treatment that takes the value of 0 for the placebo group and 1 for the Pravastatin group. Identify the parameter estimates in the model. (Enter your answers for the intercepts rounded to three decimal places, and for the slope rounded to four decimal places.) Find the straight line equations for the placebo group and for the Pravastatin group. (Enter your answers for the intercepts rounded to three decimal places, and your answers for slopes rounded to four decimal places.) ( μy placebo and μy pravastatin)